Ultrastructural analysis of pancreatic carcinogenesis. III. Multifocal cystic lesions induced by N-nitroso-bis(2-hydroxypropyl)amine in the hamster exocrine pancreas.

Hamsters were given weekly injections of the pancreatic carcinogen N-nitroso-bis(2-hydroxypyropyl)-amine for up to 44 weeks. The cystic foci induced by this treatment, which are putative precursor lesions, were studied by high resolution light microscopy and electron microscopy. They were found to consist mainly of cells that closely resembled those of hamster pancreatic adenomas and adenocarcinomas, confirming their status as precursors of these tumors. However, they additionally contained cells that possessed acinar cell characteristics, raising the possibility that dedifferentiated acinar cells might be involved in the histogenesis of the foci and thus of the pancreatic tumors.